Process for dehairing hides and skins and preparing them for tanning



Patented June 24, 1930 UNITED STATES PA'rENr orric waste CHARLES JOSEPHMICHEL MARIELE TETIT, OF- PARIS, FRANCE, ASSIGNOR, BY DIRECT AND MESNEASSIGNMENTS, 'IO ROHM AND HAAS COMPANY, OF PHILADELPHIA, PENNSYLVANIA, ACORPORATION OF DELAWARE PROGESS FOR DEHAIRING HIDES AND SKINS ANDPREPARING THEM FOR TANNING No Drawing. Application fi led May 21, 1926,Serial N6. 110,816, and in France April 18, 1925.

This invention relates to a process for dehairing hides and skins andpreparing them for tanning. It relates especially to the preparation ofhides to'be tanned by using certain varieties of muccdinaceca which havenot been used before my invention for this purpose. The inventionincludes special ways of proceeding in the preparation of the culturesand the operating media, and more particularly in connection with theuse of seeds or seedworts that areto be used for the culture medium.

I have discovered that Aspergz'llus org cue and similar Aspergilli, aswell as certain varieties of mucor, are capable of producing proteolyticenzymes which are especially useful in connection with the process ofdehairing hides and skins and in the preparation of the same fortanning. The species Aspe-rgillns oryzw is particularly applicable forthis use.

T have also discovered that it is not neces sary to sterilize bran orother medium for the culture of mucedinacecc by heat before it is sownwith the spores of the selected mucedinaccee. T have found instead thatthe culture medium may be impregnated with various substances insolution, such as salicyllate of soda, formic aldehyde (methylaldehyde), lactic acid, pure tannic acid, or with tanning extracts, andmore particulan ly quebracho extract. Tanning extracts have been foundto be especially useful in this connection.

The culture medium, such as bran, or grain, or grain wort impregnatedwith one or more of the substances above mentioned that effect a kind ofsterilization has proven to' cause a selective and rapid growth ofvarieties of mucedz'nacere that is particularly adapted for use indehairing 'hides. The use of these materials in practice has indicatedthat the culture medium appears to undergo a relative sterilization, andis so conditioned that the varieties of mucedinaceaa that,are suitablefor dehairing purposes are selectively grown, and the desirable speciesare propagated more rapidly, and the less desirable species are, inlarge measure, pre vented from developing.

The following is given by way of example as a particular illustration ofthe invention. About 100 parts by weight of bran may have added theretoabout an equal weight of an aqueous solution containing 15 per centquebracho extract. This culture medium will cause almost exclusivepropagation of Aspergz'llus org 2w, after fertilization with the s oresof this species.

As another example, it may be mentione that seeds or wort of fermentedgrain, such as caster beans, corn, wheat, cotton, etc., may be mixedwith a suitable amount of lactic acid, either before or aftersaccharification or fermentation, and then seeded with Asper'gillas org2w by means of the culture on bran and quebracho. For this purpose,about 50 per cent of a 5 per cent aqueous solution of lactic acid may beused to saturate or impregnate 100 parts by weight of the grain. ()nsuch a culture medium the species develops quickly and almost exclusively, and the secretion of the proteolytic enzymes is very abundantand very active.

The medium containing the enzymes is diluted by adding a suficientamount of water and the product is used for dehairing hides, skins, etc,by immersing the hides, etc, and permitting the same to remain thereinfor the required length of time. The

reaction for producing the proteolytic enstances c'ontained in the rootsof the hair and in the skin is very noticeable because of the ammoniathat is evolved during the reaction.

Instead of dehairing the hides as mentioned above, the process may becarried out by using the cultures of wmcedinaceae on bran alone,especially cultures of ASPQT'Q'Z'L Zus org 2w, for dehairing the hidesand the skins. The process may be carried out by adding 100 parts of anacqueous solution containing about 5 per cent of lactic acid to aboutlOOparts of bran, and this medium may be seeded with the spores ofAspergillm 01-year. When the culture has been in progress for a suitablelength of time, varying from 36 to 48 hours, giving time formyobjectionable amount of spores have been formed, the mass is trituatedin a suitable quantity of water. Sodium fluoride or other preservativemay be added to the acqueous dilution in amounts ranging between 0.1 percent and 5 per cent, and the dilution may be used directly for dehairinghides and skins, the dehairing taking place in a few hours.

I claim:

1. In the process of unhairing and bating hides and skins the step whichcomprises subjecting them to the action of a solution zontaining theculture of mucedinaceous ungi.

2. In the process of unhairing and hating hides and skins the step'Which comprises subjecting them to the action of a solution containingthe culture of Aspergillus org 2w.

CHARLES JOSEPH MICHEL MARIE LE PETIT.

